Stable preparations



Patented May 19, 1936 UNITED STATES STABLE PREPARATIONS Ludwig Zeh, Leverkusen-Wiesdorf, and Erich Konrad, Leverkusen-L G. Werk, Germany, as- .signors to Durand & Huguenin Aktiengesellschaft, Basel, Switzerland, a corporation of Switzerland No Drawing. Application February 4, 1935, Serial No. 4,990. In Germany February 15, 1934 7 Claims.

The present invention relates to new stable preparations comprising salts of leuco sulfuric acid esters of vat dyestuffs of the benzanthrone series.

,Dyeing and printing preparations containing salts of leuco sulfuric acid esters of the benzanthrone series are liable to decompose while regenerating the unchanged dyestuff, thus diminishing the lifetime of the preparations and the yield of the dyestufi. It is, therefore, a problem to do away with these disadvantages in a simple and convenient manner.

We have now found that water soluble salts of mercapto compounds have an excellent stabilizing effect upon the leuco sulfuric acid esters in question. In accordance therewith our present invention is concerned with stable: dyeing and printing preparations comprising salts of leuco sulfuric acid esters of vat dyestuffs of the benzanthrone series and water soluble salts of mercapto compounds. The presence of the said mercapto compounds in the dyeing and printing preparations results in a much better yield of the leuco ,sulfuric acid esters in question even after some days standing, and in some cases has made it technically feasible for the first time to employ such leuco sulfuric acid esters of vat dyestuffs of the benzanthrone series, which up to the present time could not be stored in form of the pastes owing to their tendency to decompose. The stabilizers can be added to the dyestuffs either prior to or after the preparation of the dyeing and printing pastes and even to the dyeing baths; in accordance therewith the term dyeing and printing preparations used in the claims is notrestricted to solid preparations or pastes but is intended to embrace likewise dyeing liquors although the employment of our stabilizers in solid preparations or in pastes of the character described is the preferred form of our invention.

As to the nature of the stabilizer we wish to point out that our inventionis in no way restricted to any particular class of compounds it being to be understood that every salt of a compound which contains a mercapto group is operative for the purpose in question. Our stabilizers are employed in form of water soluble salts, preferably alkali metal or ammonium salts, although other water soluble salts, such as piperidine salts, are not excluded from the scope of our invention. As examples there may be mentioned:-Water soluble salts of thioglycolic acid, thiophenols, mercaptobenzothiazoles, xanthogenic acid, thiosalicylic acid etc. Among the mercapto compounds dithiocarbamic acids have proved to be particularly suitable the eflicacy being increased with an increase of the alkalinity of the product. Thus compounds in which the hydrogen atoms of the amino groups are wholly or partly replaced by alkyl groups which may be of a cyclic nature show a better stabilizlng effect than dithiocarbarnic acid itself or aryl derivatives thereof.

In the following there is given one example for a printing preparation and one example for a dyeing preparation it being to be understood that as stabilizers there have proved to be suitable the water soluble salts of mercaptobenzothiazole, 3- methoxyphenylmercaptane, thioglycolic acid, Xanthogenic acid, thiosalicylic acid, dithiocarbamic acid of the formula,

N-dimethyl-dithiocarbamic acid of the formula,

thiocarbamic acid, for instance, in form of its piperidine or potassium salt, dimethyland diethyl-dithiocarbamic acid, furthermore, hydrogen sulfide or trithiocarbonic acid.

As dyestufl? component there is described in the examples the leuco sulfuric acid ester of the olive green dyestuif described in Example 7 of application Zeh et al., Serial No. 634,076. Among the few known representatives of the class of leuco sulfuric acid esters of the benzanthrone series there have been investigated with a similar good result the leuco sulfuric acid esters of the following dyestufis:-

1. The olivedyestuff obtainable by. fusing 10 parts of di- (1'-anthraquinonyl) -6-Bz-diaminobenzanthrone with 40 parts of caustic potash and 25 parts of alcohol at 180 C. to 200 C., boiling the melt with water, filtering and washing as is described, for instance, in British Patent 337,741. f

2. The dyestufls obtainable in accordance with Printing P eparation 10 parts byweight of a pasty sodium salt of the leuco sulfuric acid ester of the olive green dyestuilf described in Example 'I of application Zeh et al.,'Berlal No. 834,076 (the paste containing 20% of the dyestufl') are stirred into a thickening containing Parts by weight Thiodiethyiene glycol 5 Water 25 Neutral starch tragacanth thickening Diethyltartrate 5 30% solution of sodium chlorate 4 1% solution of the vanadate of ammonia 2 Stabilizer. l

The printing paste thus obtained is applied on cotton in the usual manner. The material thus printed is then steamed in the Mather-Flatt for 5 minutes, rinsed, soaped at the boil and rinsed a second time. Very equal and strong shades are thus obtained even after some days standing of the printing pastes.

Exam: 2

BMW preparation 800 grams of a pasty dyeing preparation containinglfiogramsofthedyestuifdescribedin mmplelinformofitssodiumleucosulfm-ic acid ester salt and grams of the stabilizer are dissolved in 200 litres of water, 40 kgs. of bleached mercerized cotton are dyed therein at about 40 to 50 C., the developing being then eflected by 800 grams of sodium nitrite and 10 kgs. of sodium sulfate and a subsequent treatment with hydrogen sulfide. The cotton is then rinsed, neutralized by means of ammonia and washed.

In the slop-padding our preparations can be employed in a similar manner.

we claim:-

1. Dyeing and printing preparations comprising salts of leuco sulfuric acid esters of vat dyestufis of the benzanthrone series and water soluble salts of dithiocarbamic acids.

2. Dyeing and printing preparations comprising salts of leuco sulfuric acid esters of vat dyestuffs of the, benzanthrone series and water soluble salts of alkyl substituted dithiocarbamic acids.

3. Dyeing and printing preparations comprising salts of leuco sulfuric acid esters of vat dyestuffs of the benzanthrone series and water soluble salts of dialkyldithiocarbamic acid.

4. Dyeing and printing preparations comprising salts of leuco sulfuric acid esters of vat dyestuffs of the benzanthrone series and water soluble salts of pentamethylene-dithiocarbamic acid.

5. Dyeing and printing preparations comprising a salt of the leuco sulfuric acid ester of a vat dyestuif of the benzanthrone series and the piperidine salt of pentamethylene-dithiocarbamic acid.

6. Dyeing and printing preparations comprising a salt of the leuco sulfuric acid ester of a vat dyestuff of the benzanthrone series and an alkali metal salt of diethyl-dithiocarbamic acid.

7. Dyeing and printing preparations comprising a salt of the leuco sulfuric acid ester of a vat dyestuil of the benzanthrone series and an alkali metal salt of dimethyl-dithiocarbamic acid.

LUDWIG ZEH. ERICH KONRAD. 

